1. Field of the Invention
Embodiments of the invention relate to a device and a method for working in the presence of electromagnetic fields, in particular fields occurring in cautery applications.
2. Description of the Related Art
Although cautery applications are becoming increasingly important in medicine, particularly in surgical procedures and in conjunction with damaged vessels, such applications are contraindicated for some patients. Such contraindication may result from an at least partially implanted medical device (also referred to below as “implant” or “IMD”), in particular for so-called implanted cardiverter-defribillator (ICD) patients.
Cautery applications in the prior art primarily involve electrical cautery, i.e., cautery that is carried out using an object, for example a thin wire, which is heated by current flow. Cautery is also referred to as “diathermy”. Distinctions are made among electrical high-frequency diathermy, ultrasonic diathermy, and microwave diathermy. Ultrasonic diathermy is generally considered to be noncritical for IMD wearers, whereas high-frequency diathermy and microwave diathermy may interfere with an IMD.
To still allow cautery applications, in particular using high-frequency diathermy and microwave diathermy, primarily asynchronous operating modes for pacemakers and ICD patients are known. These have the disadvantage that a considerable proarrhythmic risk results from asynchronous stimulation. Unnecessary asynchronous stimulation is contraindicated, especially for ICD patients.
Currently known interference detectors for all established pacemaker (IPG) and ICD systems cannot be used for this purpose, since such detectors depart from asynchronous interference mode immediately after onset of the interference. Thus, these detectors fail in the presence of pulsed interferences, which occur in cautery applications, among others.